20211221111999 has 16 divisors (see below), whose sum is σ = 20708664861792. Its totient is φ = 19719778434048.

The previous prime is 20211221111863. The next prime is 20211221112007. The reversal of 20211221111999 is 99911112211202.

It is a cyclic number.

It is not a de Polignac number, because 20211221111999 - 2¹⁶ = 20211221046463 is a prime.

It is a super-2 number, since 2×20211221111999² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211221141999) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10082027 + ... + 11919299.

It is an arithmetic number, because the mean of its divisors is an integer number (1294291553862).

Almost surely, 2^{20211221111999} is an apocalyptic number.

20211221111999 is a deficient number, since it is larger than the sum of its proper divisors (497443749793).

20211221111999 is a wasteful number, since it uses less digits than its factorization.

20211221111999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1838906.

The product of its (nonzero) digits is 11664, while the sum is 41.

The spelling of 20211221111999 in words is "twenty trillion, two hundred eleven billion, two hundred twenty-one million, one hundred eleven thousand, nine hundred ninety-nine".